Harvesting sunflowers is facilitated by using specialized header arrangements on the front end of a combine to cut the stalks and gather the sunflower heads into the combine. Sunflowers grow relatively tall and the seeds are present in a head at the top of the stalk. These seed heads are relatively large and heavy, such that when the sunflower plants are mature and ready for harvesting the top of the stalks are commonly bent over with the heads hanging down and the top portion of the stalk shaped like a hook.
A typical conventional combine header reel has a rotating center shaft mounted at each end to the combine header and rotated by a reel drive. A plurality of contact members are mounted to the shaft in a horizontal orientation spaced radially from the shaft. In a typical reel, the contact members are mounted to the shaft by attaching plates or arms perpendicular to the shaft and spaced therealong extending radially from the shaft and mounting the contact members to the periphery of the plates or ends of the arms. The contact members are configured so that as the shaft and contact members rotate the contact members contact standing crop plants and move them rearward into the cutter bar and onto the header table where same are gathered into the combine.
These conventional header reels include fixed blade reels and pickup reel. In a fixed blade reel the contact members are blades that are fixed to the shaft with a face oriented substantially radially, and as the shaft rotates the faces of the blades move rearward toward the header and contact the plants as the header moves forward, pushing the plants toward the cutter bar and header table. In a pickup reel the contact members are horizontal finger tubes mounted to the shaft by mounting on the periphery of the plates, with fingers mounted to the tubes. The fingers pivot about a tube axis so the angle of the fingers varies as the reel rotates. The orientation of the fingers is dictated by a linkage so the fingers on the bottom portion of the reel always point generally downward as the reel rotates, and the fingers act to reach down and pick up crop slightly ahead of the cutter bar.
Such a pickup reel is disclosed in U.S. Pat. No. 4,156,340 to Colgan et al. and U.S. Pat. No. 6,502,379 to Snider. U.S. Pat. No. 7,856,801 to Remillard discloses a blade conversion for mounting over the fingers of a pickup reel to in light crops where the plants are spaced apart and the fingers pass through the plants instead of engaging same and sweeping them into the cutter bar. These conventional fixed blade and pickup reels are well suited to crops such as cereals, oilseeds, and pulse crops.
When harvesting sunflowers the contact members contact the stalk somewhat below the heads and sweep the stalk into the cutter bar. The stalk is cut off but often the hook of the cut off stalk hangs on the contact members with the stalk on one side and the head hanging on the other side. As the contact member moves about the rotational axis the hook of the stalk simply rotates about the contact member where it is hooked and remains hanging as the reel rotates. The head and stalk do not fall onto the header table but remain hanging on the blade/bar, tangling with further stalks as the header moves forward.
With pickup reels as well, the fingers often spear the sunflower seed heads and carry them around as the reel rotates. It is known to mount a cover over the fingers to make a flat surface instead of spaced apart fingers to facilitate harvesting sunflowers.
Various reels with unconventional configurations have been developed for harvesting sunflowers. For example U.S. Pat. No. 4,445,314 to Gust discloses a reel with two curved opposite faces where the rotational axis is at a mid-point of the faces and the outer edges are rounded. With the entire reel smooth and rounded in this manner, when it rotates to urge sunflower stalks into the combine there is nowhere for the stalks to hang. Similarly U.S. Pat. No. 4,589,250 to Faul, Jr. discloses a tubular reel with short fingers extending from the tube, and U.S. Pat. No. 4,255,920 to Janzen discloses a reel with three solid smooth faced blades, again leaving nowhere for the stalks and hanging heads to hang.
Significant costs and time are required to remove the conventional fixed blade or pick-up reel, which is still required for many crops, and replace it with a reel more suited to harvesting sunflowers.